Following a great 2013, shares of Alaska Air Group seem poised to fly even higher above competitors on the wings of great customer service and expanding flight routes.

In an industry as volatile as the airline space, it is best to invest in the highest-quality companies. These are companies that have proven continuously that they operate at higher levels than peers. When it comes to regional airliners, no company has been more consistent than Alaska Air Group(NYSE:ALK). The company's industry-leading fundamentals help it stand out from competitors like JetBlue Airways(NASDAQ:JBLU) and Hawaiian Holdings(NASDAQ:HA).

Record earningsAlaska Air Group recently reported record fourth-quarter earnings. The company earned net income of $77 million, or $1.10 per diluted share, which easily beat 2012's comparable quarter earnings of $50 million, or $0.70 per diluted share, and represents year over year growth of over 50%. The results also easily beat the average analyst estimate, which called for $1.07 per diluted share.

The full 2013 fiscal year earnings results for Alaska Air Group were equally impressive. The company earned a record net income of $383 million, or $5.40 per diluted share. These results easily surpassed 2012's results, which stood at $339 million net income, or $4.73 per diluted share.

Revenue for Alaska Air Group came in at $1.21 billion, which was in line with consensus estimates of $1.2 billion. However, revenue for the fourth quarter still grew 6.9% on a year-over-year basis.

Industry-leading fundamentalsIt is difficult to not put a premium on fundamentals in an industry where so few companies make them a priority. Alaska Air Group remains the best company in the space in many regards. The following is a breakdown of some of the company's key metrics compared to competitors JetBlue Airways and Hawaiian Holdings:

Company

Alaska Air Group

Hawaiian Holdings

JetBlue Airways

Market cap

5.53B

561.59M

2.61B

Debt

912.2M

762.74M

2.85B

Cash

1.44B

441.48M

954M

ROIC

16.94%

0.93%

0.62%

Net profit margin

9.33%

1.48%

2.32%

Dividend/Yield

$0.80/1%

NA/NA

NA/NA

As the data above indicates, no other regional airliner is even close to Alaska Air Group in terms of the key listed metrics. Since the airline space is notorious for large debt, it is impressive to see Alaska Air Group stand out in this regard. With only $912.2 million in debt, equal to only 16.5% of the company's market capitalization, Alaska Air Group fares the best. The company's cash hoard of $1.44 billion is also particularly impressive.

However, most important of all is the company's return on invested capital, or ROIC, metric, which stands at an impressive 16.94%, and indicates that management is very efficient at managing capital and investing in company operations. Additionally, Alaska Air Group's net margin leads all other competitors and it remains one of the few companies in the entire airline space to pay a substantial dividend.

With regard to fundamentals, Alaska Air Group is flying first class while its competitors remain stuck in coach.

Future growthAlaska Air group is set to grow well in 2014. Revenue is expected to increase 5.3% and EPS is expected to grow an impressive 19.1%. This growth is due in large part to the company's continued rollout of new nonstop-flight routes such as Seattle to Colorado Springs, Portland to Tucson, and San Diego to Boise. All told, the company added ten new nonstop flight routes in the fourth quarter. It is planning another seven new routes during the first half of 2014 as well.

Of course, as I've mentioned before, the company's largest asset is its impeccable track record with regard to customer service. As long as Alaska Air Group keeps putting customers first, the company should continue to be one of the most popular brands to fly with and growth is almost assured as long as new routes are added incrementally.

Flying highDespite a soaring stock in 2013, Alaska Air Group is still a great investment. It is also the only company that I can recommend in the regional airline space. With the best fundamentals by far and solid growth projections, Alaska Air Group should continue to fly above competitors in 2014.